Detroit Speed Leaf Springs
 
This page shows the practical application of both spring sets. For my car--a fairly light '68 with short tires--DSE 3" springs are the way to go. Here's why:
 

   


Tires are short 285/35-18 Nitto's on 18"x10" wheels. 5.5" back, I believe.
With low curb weight, my car sits too high with DSE 2" springs. So....
So I installed 1.5 lowering blocks. Ride height after 800mi, Full tank of gas.
The lowering blocks affected wheel centering and traction.
It ain't easy filling wheelwells on a 67-68. DSE to the rescue with 3" spri...
Your car may need 2" springs. Tire dia, weight & body style affect ride ...
'Bout 1.75" tire to wheelwell lip clearance with 2" springs / 1.5" blocks.
Flowmaster tailpipes might interfere with "flat" 3" springs.
My tailpipe location is limited by a CE shock crossmember.
Note how spring perches barely straddle the leaf springs. Not good.
1.5" Lowering blocks. I would not recommend more than a 1" block.
These are beefy Landrum rear shackles and bushings.
The 3" leafs (bottom) are noticably flatter.
The difference in arch should eliminate the need for lowering blocks.
Subtract 1/2 the spring eye dia. to get free arch. DSE 2's measure 6" and....
DSE 3" springs measure about 4" free arch. Many variables affect ride height.
Looks like DSE has upgraded the spring design. 2" springs are in back.
DSE leaf springs feature high durometer rubber front bushings.
Extruded aluminum lowering blocks from Speedway Motors 1", 1.5" and 2"
I'll say it again. Try not to run more than a 1" lowering block (right).
Alright!! Here we go. 3" springs without blocks with an empty gas tank.
New ride height with 3" springs is same as DSE 2" springs with blocks.
I'll rack up some miles and take new pix with a full fuel load. So far so good.
This is how it should look. Top of the tire should be well above the beltline
Looks like a lot of stance here. But the car is almost dead level.
I might take a turn out of the front coilovers after the leaf springs settle.
After some miles with a full tank.
Short tires on a 67-68? DSE 3's are the way to go.